It's effectively endorsed another bidder, Liberty House, elevating the latter to a favourable position in the sale process.

Liberty House

Metals tycoon Sanjeev Gupta's Liberty House is expected to reference Excalibur in its own bid, saying it will welcome the management buy-out group's support in the deal.

However, City A.M. understands that Liberty House would press ahead with its bid even if Excalibur did not tie-up with the investor at a later stage, and Liberty House is not seeking to support the management group’s deal.

Greybull Capital

Turnaround specialist Greybull Capital bought Tata's Scunthorpe-based long products division for a nominal fee of just £1 in April. The deal means the steelworks business will be renamed as British Steel.

But it's a lot smaller than the sprawling Port Talbot site, while Greybull isn't a specialist steel company with any particular expertise.

Hebei Iron and Steel Group

China's biggest steelmaker, Hebei Iron and Steel Group, could be seen as a surprising candidate given its role in the industry's current crisis. But it agreed to buy a Serbian steel plant in April last month. This is part of its bid to expand overseas and shift capacity abroad to weather a slowing economy at home.

JSW Steel

India's second largest steel maker, JSW Steel, wants to expand by setting up plants in new locations. However, is it the best candidate to buy Tata's UK operations? UBS said in a note: "For JSW Steel specifically, we note their poor track record of overseas expansion and a relatively stretched balance sheet."

Nucor

The US' largest steel producer was one of four firms to bring an anti-dumping investigation into imports of Chinese and Japanese cold-rolled flat steel products to the US Commerce Department. The the US recently said it would slap Chinese imports with a five-fold tax hike, in what's been described as an escalating trade war.

Endless

Leeds-based private equity investor specialises in turning around loss-making companies such as Crown Paints. It's also bought Kiddicare from supermarket group Morrisons, as well as Bathstore.